The absence of any of the three types of cones is what accounts for different types of color blindness. S-cones (short-wavelength absorbing cones) help us see blue, M-cones (medium-wavelength absorbing cones) reveal green and L-cones (long-wavelength cones) interpret red light. The human eye contains three different types of cones. All types of color blindness have to do with diminished (or absent) functionality in the cones. The human eye has eighteen times more rods than cones.īut the cones are what give us fine detail and color.

They are the reason your eyes will adjust in a dark room, allowing you to see basic shapes. Named after their shapes, they are called rods and cones. Our eyeballs have two kinds of photoreceptors in the retina that are designed to absorb light. To understand the multiple types of color blindness that exist, it can be helpful to briefly review the basic mechanisms of human vision. There are seven official diagnoses of color blindness: four different types of color blindness fall in the red-green category, two are in the blue-yellow spectrum and one version describes a type of vision completely lacking in color. What are the different types of color blindness?

The physiological manifestations of each are the same, though. To make navigation of the topic even more interesting, variations can be further divided into inherited and acquired types of color blindness. The categories are nested, and some versions that are designated as distinct conditions manifest in similar ways. The question of how many types of color blindness exist can be confusing.

Green red color blind test for kids